Cataracts involve a clouding of the eye’s natural lens, which normally focuses light for clear vision. This clouding can make vision appear hazy. Increased eye pressure, or intraocular pressure (IOP), refers to the fluid pressure within the eye. A healthy eye maintains this pressure within a range of 10 to 21 millimeters of mercury (mmHg). This article explores how cataracts can influence elevated eye pressure.
The Link Between Cataracts and Eye Pressure
Cataracts can lead to increased eye pressure, though not every cataract causes this complication. This relationship is particularly noted with advanced or mature cataracts. As a cataract progresses, physical changes within the lens can interfere with the eye’s natural fluid drainage system. The eye continuously produces aqueous humor, a fluid that normally drains to maintain stable pressure. When this drainage is disrupted by the cataract, pressure can build up inside the eye.
How Cataracts Can Increase Eye Pressure
Several mechanisms explain how a cataract can lead to elevated intraocular pressure.
Phacomorphic Glaucoma
One mechanism is phacomorphic glaucoma. This occurs when the cataract-affected lens swells significantly as it matures, pushing the iris forward. This physical displacement can narrow or block the drainage angle, the area where aqueous humor typically exits the eye. This blockage leads to a buildup of fluid and pressure.
Phacolytic Glaucoma
Another mechanism is phacolytic glaucoma, which arises from a very mature cataract. Proteins from the cataractous lens leak into the eye’s anterior chamber. These leaked proteins can clog the trabecular meshwork, the primary drainage system of the eye. This clogging impedes fluid outflow, resulting in increased intraocular pressure and often inflammation within the eye.
Pupillary Block
A third mechanism is pupillary block. When the lens becomes swollen, it can press against the back surface of the iris. This contact obstructs the normal flow of aqueous humor from the posterior chamber (behind the iris) to the anterior chamber (in front of the iris). As fluid accumulates in the posterior chamber, pressure builds up behind the iris, pushing it forward and potentially closing the drainage angle.
Recognizing Symptoms and Professional Diagnosis
When a cataract causes increased eye pressure, individuals may experience a range of symptoms. These can include eye pain, noticeable redness, and sudden blurred vision. Some may also report seeing halos around lights, headaches, or nausea. Such symptoms indicate a significant rise in intraocular pressure and require an immediate visit to an eye care professional.
Professional Diagnosis
Diagnosis involves a comprehensive eye examination to assess the underlying cause of elevated pressure. Eye care specialists use tonometry to accurately measure intraocular pressure. An examination of the drainage angle, known as gonioscopy, helps determine if the angle is open, narrowed, or closed. The optic nerve is also assessed for any signs of damage, as sustained high pressure can lead to optic nerve damage.
Treating Cataracts and Managing Eye Pressure
If a cataract is identified as the cause of increased eye pressure, cataract surgery is often the definitive treatment. This procedure involves removing the cloudy natural lens and replacing it with a clear artificial intraocular lens. Removing the swollen or protein-leaking cataract eliminates the physical obstruction or the source of inflammatory proteins that were impeding fluid drainage, thereby normalizing eye pressure.
If eye pressure remains elevated after cataract removal or if there is pre-existing glaucoma, additional treatments might be necessary. These can include pressure-lowering eye drops, laser procedures, or further surgical interventions aimed at improving fluid outflow from the eye. Post-operative monitoring and ongoing eye care are important to ensure that intraocular pressure remains controlled and overall eye health is maintained.